Each year, businesses generate tons of waste including large amounts of used paper. A significant percentage of the used paper is recycled. Recycling reduces the amount of waste going into landfill and also saves natural resources used to manufacture new paper. Such savings can be significant, for example, one ton of high quality paper typically requires four tons of green wood.
Paper recycling traditionally occurs in large dedicated recycling facilities. The recycling facility receives used office paper from a general geographic area and processes the paper to create new sheets of paper. A traditional recycling facility includes large repulper machines which use mechanical action to break down paper into individual fibers. Wet chemical treatments are used to remove inks from the fibers. The resulting material is then reconstituted to form a low grade recycled paper.
Such methods of recycling paper are expensive and wasteful. One disadvantage of using centrally located recycling facilities is the personnel time and energy expenditures used to transport the used paper from a geographic region to the central recycling facility. A second disadvantage is the waste involved in exposing all the pulp to a bleaching agent when only a small percentage of the paper may be marked. A third disadvantage of present recycling systems is the low quality of the resulting recycled paper. Breaking down the sheet of paper and using the resulting paper pulp to reconstitute a recycled sheet of paper produces a low grade paper unsuitable for use in laser printers, and other office applications.
An alternative method of recycling paper uses solvents to soften and lift-off toner particles from the paper as described in U.S. Pat. No. 5,632,856 issued to Buie. The Buie reference describes a method of removing toner by pressing a preheated plastic film against a paper sheet. The toner fuses to the plastic ink film and is lifted from the paper sheet being recycled. The recycled sheet of paper is then rehumidified, calendarized and treated with toner to restore whiteness. The paper is also inspected to determine whether holes have been generated where the plastic has removed toner.
The method described in the Buie reference improves upon traditional recycling techniques but still suffers from the need to use expensive specialized equipment and is limited to recycling only paper marked with toners that can be removed using a preheated plastic film. Finally, the Buie method is harsh on the paper. Thus after the film is lifted off, the paper is rehumidified and inspected for possible holes generated where the plastic removed the toner.
Thus an improved method for recycling paper is needed.